HMDS (Head Mounted Display Systems) have been found to facilitate a variety of recreational, educational and vocational endeavors. HMDS render holograms and other information within immersive mixed reality environments, such as augmented reality environments and virtual reality environments.
The imaging performed by HMDS occurs in very close proximity to the users' eyes, making it desirable to render the images with a high degree of precision and resolution. However, optical and computational components that are required to render high quality images within such a small form factor are economically and computationally expensive.
MEMS (Micro Electrical Mechanical Systems) mirrors systems represent one technological advance for rendering high quality images more efficiently with HMDS. MEMS mirrors system are configured with one or more modulating mirrors that scan light from a light source, such as an RGB (Red, Green, Blue) laser assembly, and redirect that light to the individual pixels of a target display to thereby generate each frame for the images that are rendered by the HMDS.
RGB laser assemblies used with MEMS mirrors systems typically include separate red, green and blue laser diodes, as well as three correspondingly separate collimating optics. Each of the collimating optics is configured to separately collimate and direct the light from their correspondingly different laser diode to a beam combiner. The beam combiner combines the individually collimated beams of red, green and blue light into a single beam of light that is redirected to the MEMS mirrors system. In this manner, the RGB light is spectrally combined prior to scanning by the MEMS mirrors system.
An example of a typical RGB laser assembly 100 used in combination with a MEMS mirror system 110 is shown in FIG. 1. As shown, the RGB laser assembly 100 includes a red laser diode 110r, a green laser diode 110g and a blue laser diode 110b. The red laser diode 110r generates red light 112r that is collimated by a first collimating optic 120r. The green laser diode 110g generates green light 112g that is collimated by a second collimating optic 120g. And, the blue laser diode 110b generates blue light 112b that is collimated by a third collimating optic 120b. 
The collimated beams of red light 112r, green light 112g and blue light 112b are then spectrally combined by the optics of beam combiner 130 and redirected to a MEMS mirror system 140, which performs a scanning process that redirects the light to the individual pixels of a target display. More specifically, a graphics processor or chip, not shown, sequences pulsing of the RGB lasers and modulation of the MEMS mirrors in such a manner that the RGB light beams are redirected to the correct pixels of a target display with the appropriate timing for rendering each pixel of each image frame. For instance, the pulsing of the lasers and the scanning modulation processes are performed iteratively at a very high frequency to accommodate the rendering and refresh rate of the HMDS (e.g., 60 Hz-120 Hz or even faster frame refresh rate).
An existing problem with current MEMS display systems is that many of the costs associated with the laser and optical components are essentially tripled. In particular, the RGB laser assembly 100 has three separate laser diodes, submounts, and packages (110r, 110g and 110b), as well as three correspondingly separate collimating optics (120r, 120g and 120b), each of which adds to the overall cost of the laser assembly. Additionally, the dichroic mirrors used for wavelength combination can be expensive and bulky, increasing the cost and size of the overall assembly. Sometimes, a separate photo-diode component (e.g., photo-diode 150r, 150g and 150b) is also paired with each laser, which further adds to the cost. Utilizing three separate collimators, along with three separate photo diode components (including the wiring for connecting these components), increases the overall size of the RGB laser assembly. However, this is an undesirable attribute for an RGB module, particularly since HMDs require the display systems to be as small as possible, both for aesthetics and functionality.
Yet another problem associated with MEMS display systems is that the scanning of the individual red, green and blue light beams is not always perfectly aligned within the target pixel(s) being scanned, despite the use of the three collimating lenses. For instance, as shown in FIG. 1, MEMS mirror system might scan the pulsed red light 112r, green light 112g and blue light 112b in such a way that the red light 112r, green light 112g and blue light 112b do not perfectly overlap on the target pixel location 190. This can result from various factors, including variability between the laser diodes, misalignment in the disparate collimating optics and inappropriate sequencing of the timing for pulsing the different laser diodes with the modulation of the MEMS mirrors.
Active horizontal and vertical alignment of the light beams within the target pixel location can sometimes resolve this misalignment by calibrating/resequencing the timing of the individual laser diode pulses with the modulation of the MEMS mirrors (e.g., by pulsing the laser diodes more quickly or more slowly). This calibration/alignment process can sometimes be performed to correct for minor misalignments of RGB light, but existing systems limited the correction to less than 10 pixels in the horizontal and vertical directions since the RGB lasers are already co-aligned in existing systems.
Despite the foregoing advances, there is an ongoing need and desire for enabling HMDS to be made more compact, and for the imaging to be performed more precisely and efficiently, as well as for reducing the associated economic costs of the HMDS imaging components.
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced.